1. Field of the Invention
The invention relates to a method for initiating a plurality of subscriber identity cards, and more particularly to a method for initiating operating voltages of the subscriber identity cards in a system.
2. Description of the Related Art
Currently, the Global System for Mobile communication (GSM) standard is the popular standard for mobile phones in the world. The GSM standard, standardized by the European Telecommunication Standards Institute (ETSI) is a cellular network structure and a Time Division Multiple Access (TDMA) system. For a carrier frequency, the TDMA system will divide a frame into eight time slots, wherein each time slot is used to transmit a channel data for a subscriber. In addition, the General Packet Radio Service (GPRS) technology is one of the available technologies of a GSM network. The GPRS technology utilizes the unused channels in the GSM network to provide moderate speed data transmission. The Wideband Code Division Multiple Access (W-CDMA) is a wideband spread-spectrum mobile air interface that utilizes the direct-sequence spread spectrum method of asynchronous code division multiple access to achieve higher speeds and support more users compared to the implementation of time division multiplexing (TDMA) used by 2G GSM networks. Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) is another type of 3G mobile telecommunications standard.
A dual SIM mobile phone is a phone with two Subscriber Identity Modules (SIMs), which correspond to different numbers. The dual SIM mobile phone allows a user to use two communication services without carrying two phones at the same time. For example, the same mobile phone may be used for business and private use with separate numbers and bills, thus providing convenience to mobile phone users. Typically, a SIM controller installed in the mobile phone drives two SIMs with a fixed voltage level. However, when the operating voltages of the installed SIM or Universal SIM (USIM) cards are different or the operating voltages of installed SIM/USIM cards are different from the driving voltage level, the (U)SIM cards malfunctions.